High-frequency module device

ABSTRACT

The present invention provides a high-frequency module configuring a micro communication functional module, which includes a base substrate ( 2 ) which has multiple pattern wiring layers ( 6   a ) ( 6   b ) ( 9   a ) ( 9   b ) and dielectric insulating layers ( 5 ) ( 8 ) ( 11 ) formed therein, and has a buildup surface for smoothing the upper layer thereof, and a high-frequency element layer ( 4 ) formed on the buildup surface, which has an inductor ( 20 ) formed therein via an insulating layer ( 19 ) formed on the buildup surface. The base substrate ( 2 ) is provided with a region ( 30 ) where the pattern wiring layers ( 6   a ) ( 6   b ) ( 9   a ) ( 9   b ) are not formed from the upper layer to at least the mid portion thereof along the thickness direction, and the inductor ( 20 ) of the high-frequency element layer ( 4 ) is formed directly above the region ( 30 ).

TECHNICAL FIELD

The present invention relates to a high-frequency module for configuringa micro communication functional module having an informationcommunication function and a storage function, which is associated withvarious electronic equipments such as a personal computer, a portabletelephone, audio equipment, etc.

BACKGROUND ART

Recently, as the digitization of data has been promoted, various typesof information such as music information, audio information, and videoinformation can be easily utilized by using a personal computer and amobile computer. Under the bandwidth compression using the audio codectechnique and the video codec technique, such information is easily andefficiently distributed to various communication terminal equipments bydigital broadcasting. For example, audio and video data (AV data) can bereceived by an outdoor portable telephone.

The data transmission and reception systems have been put to practicaluse widely even in a small-sized area such as a household sincedesirable network systems have been suggested. As the network systems,there are proposed various wireless communication systems for the nextgeneration such as a narrow band radio communication system of 5 GHzshown in the IEEE 802.11a, a radio LAN system of 2.45 GHz shown in theIEEE 802.11b, and a short-range radio communication system calledBluetooth.

In the data transmission and reception systems, by effectively utilizingsuch wireless network systems, various data can be transmitted andreceived easily at various places such as households and outdoorswithout using a repeater or a repeater station. Also, it becomespossible to have an access to the internet to transmit and receivevarious data.

On the other hand, in the data transmission an reception systems,small-sized portable communication terminal equipments having anabove-described communication function have to be inevitably realized.In communication terminal equipment, a transmission and reception unitis required to perform modulation and demodulation processing for analoghigh-frequency signals. Thus, in communication terminal equipment, ahigh-frequency transmission and reception circuit of the superheterodynesystem for converting transmission and reception signals to intermediatefrequency signals is generally arranged.

The high-frequency transmission and reception circuit has an antennaunit for transmitting and receiving information signals which has anantenna and a changeover switch, and a transmission/reception switchingunit for performing switching operation between transmission operationand reception operation. Also, the high-frequency transmission andreception circuit has a reception circuit which consists of a frequencyconversion circuit, a demodulation circuit, etc. Moreover, thehigh-frequency transmission and reception circuit has a transmissioncircuit which consists of a power amplifier, a chive amplifier, amodulation circuit, etc. Furthermore, the high-frequency transmissionand reception circuit has a reference frequency generation circuit forproviding the reception unit and the transmission unit with a referencefrequency.

The configured high-frequency transmission and reception circuit haslarge-sized functional elements such as various filters inserted betweenrespective stages, a voltage-controlled oscillator (VCO), an SAW filter,etc., and a great number of passive elements such as inductors,resistors, capacitors, etc. which are particular to a high-frequencyanalog circuit such as a matching circuit or a bias circuit. Respectivecircuits in the high-frequency transmission and reception circuit areconfigured in the form of ICs. However, filters inserted betweenrespective stages cannot be arranged in ICs, and therefor a matchingcircuit has to be arranged at outside of ICs. So, the high-frequencytransmission and reception circuit is large in size as a whole, whichobstacles miniaturization and decreasing in weight of a communicationterminal equipment.

On the other hand, in a communication terminal equipment, ahigh-frequency transmission and reception circuit of the directconversion system which does not convert transmission and receptionsignals to intermediate frequency signals is also used. In such ahigh-frequency transmission and reception circuit, information signalsreceived by an antenna unit are sent to a demodulation circuit via atransmission/reception switching unit to be baseband-processed directly.Also, in the high-frequency transmission and reception circuit,information signals generated by a source unit are directly modulated tosignals of a predetermined frequency band by a modulation unit withoutconverting the transmission signals to intermediate frequency signals,and thus modulated signals are transmitted from the antenna unit via anamplifier and the transmission/reception switching unit.

In the configured high-frequency transmission and reception circuit,information signals can be received by performing direct detectionwithout converting reception signals into intermediate frequencysignals. As the number of parts or elements such as filters can bereduced, the high-frequency transmission and reception circuit can haveits entire configuration simplified, and can be substantially configuredin the form of one chip. Even in the high-frequency transmission andreception circuit of the direct conversion system, filters and amatching circuit arranged at downstream stages have to be taken intoconsideration. Also, since amplification processing is performed onlyone time in a high-frequency stage of the high-frequency transmissionand reception circuit, it becomes difficult to obtain enough gain, andamplification processing has to be performed also in a baseband unit.Thus, the high-frequency transmission and reception circuit requires acancellation circuit of DC offset and an extra low pass filter, whichundesirably increases entire power consumption.

As has been described above, in the conventional high-frequencytransmission and reception circuit of both the superheterodyne systemand the direct conversion system, satisfactory characteristicsfulfilling a required specification of miniaturization and decreasingdecrease in weight of a communication terminal equipment cannot beobtained. Thus, it is proposed that the high-frequency transmission andreception circuit be configured in the form of a simplified small-sizedmodule using a Si-CMOS circuit as a base. That is, for example, there isproposed a one-chip high-frequency module in which passive elements ofhigh characteristics are arranged on an Si substrate, filters and aresonator are built in a LSI, and a logic LSI of a baseband unit isintegrated.

In the high-frequency module, when inductors are arranged on an Sisubstrate, the Si substrate is provided with holes directly under theinductors, or space is prepared between the inductors and the Sisubstrate in order to improve the characteristics of the inductors,which undesirably increases the manufacturing cost.

In case the front end of a high-frequency signal circuit is formed on asemiconductor substrate made of Si, SiGe, etc. or on a glass substrate,in addition to a high-frequency signal circuit pattern, a power supplypattern, a ground pattern, and a signal wiring pattern for performingcontrol processing are required to be formed as pattern wiring layers.As multiple pattern wiring layers are formed, there arises a problem ofmutual interference between pattern wiring layers, and also themanufacturing cost is undesirably increased.

In case the entire high-frequency module is packaged, the high-frequencymodule is mounted to an interposer (intermediate substrate) byundergoing wire bonding. However, undesirably, the area for mounting thehigh-frequency module is caused to be large and the entire thickness iscaused to be increased, and also the manufacturing cost is undesirablyincreased.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention has an object to overcome theabove-mentioned drawbacks of the prior art by providing a high-frequencymodule which is small in size and inexpensive, and can improve thecharacteristics of inductors.

The above object can be attained by providing a high-frequency module,including:

a base substrate which has multiple pattern wiring layers and dielectricinsulating layers formed therein, and has a buildup surface forsmoothing the upper layer thereof; and

a high-frequency element layer formed on the buildup surface, which hasan inductor formed therein via an insulating layer formed on the buildupsurface;

wherein the base substrate is provided with a region where the patternwiring layers are not formed from the upper layer to at least the midportion thereof along the thickness direction, and the inductor of thehigh-frequency element layer is formed directly above the region.

According to the high-frequency module employing the present invention,since the inductors are formed directly above the regions where thepattern wiring layers of the base substrate are not formed, the couplingcapacitance between the inductors and the pattern wiring layers can bereduced, and high Q value of the inductors can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-sectional view of one example of a high-frequencymodule according to the present invention.

FIG. 2 shows an enlarged detailed view of a wiring inhibition region andan inductor of the high-frequency module according to the presentinvention.

FIG. 3A to FIG. 3C show plan views showing the configuration of thewiring inhibition region at respective layers of a base substrate, inwhich FIG. 3A shows a wiring inhibition hole formed at a fourth wiringlayer, FIG. 3B shows a wiring inhibition hole formed at a third wiringlayer, and FIG. 3C shows a ground pattern formed on a second wiringlayer.

FIG. 4 shows a plan view showing the configuration of one example of theinductor.

FIG. 5A to FIG. 5C show plan views showing the configuration of theinductor at respective layers of a high-frequency element layer, inwhich FIG. 5A shows a pullout conductor pattern formed on a firstinsulating layer, FIG. 5B shows an embedded conductor pattern embeddedin a second insulating layer, and FIG. 5C shows a thin film coil patternformed on the second insulating layer.

FIG. 6 shows a plan view showing the configuration of another example ofthe inductor.

BEST MODE FOR CARRYING OUT THE INVENTION

The high-frequency module of the present invention will further bedescribed below concerning the best modes with reference to theaccompanying drawings.

FIG. 1 shows a cross-sectional view of one example of a high-frequencymodule 1 according to the present invention.

The high-frequency module 1 according to the present invention isconfigured in the form of a package (BGA etc.) to realize high-densitymounting or mounting parts or elements to a motherboard (base substrate)and to an interposer (intermediate substrate) with high density, and thehigh-frequency module 1 itself works as a functional element.

The high-frequency module 1 will be explained in detail. Thehigh-frequency module 1 includes a base substrate 2, and the upper layerof the base substrate 2 is smoothed by a smoothed layer 3, as shown inFIG. 1. Also, the high-frequency module 1 includes a high-frequencyelement layer 4 formed on the smoothed layer 3.

The base substrate 2 may be a printed-circuit board, which includes afirst wiring substrate 7 having a first wiring layer 6 a and a secondwiring layer 6 b as pattern wiring layers formed on both sides of afirst dielectric substrate 5 as a dielectric insulating layer, and asecond wiring substrate 10 having a third wiring layer 9 a and a fourthwiring layer 9 b as pattern wiring layers formed on both sides of asecond dielectric substrate 8 as a dielectric insulating layer, and thefirst wiring substrate 7 and the second wiring substrate 10 are puttogether via a preimpregnation substrate 11 as a dielectric insulatinglayer.

The first dielectric substrate 5 and the second dielectric substrate 8are preferably made of material having low dielectric constant and lowloss tangent (low tan 6), that is, material excellent in high-frequencycharacteristics. As such material, there are organic materials such aspolyphenylethylene (PPE), bsmaleimidetriazine (BT-resin),polytetrafluoroethylene, polyimide, liquid polymer (LCP), polynorbornene(PNB), etc., or ceramic, or composite materials made from organicmaterials and ceramic. Also, other than above-described material, thefirst dielectric substrate 5 and the second dielectric substrate 8 arepreferably made of material having refractoriness and chemicalresistance. As a dielectric substrate made of such material, there is anepoxy resin substrate FR-S available with comparably low cost.

The first and second wiring layers 6 a, 6 b and the third and fourthwiring layers 9 a, 9 b have functional elements such as a filter 12, acapacitor 13, and a signal wiring pattern 14, a power supply pattern 15,a ground pattern 16 for connecting these functional elements, whichpatterns are arranged in the form of a thin film using a copper foil.Also, passive elements such as inductors, resistors, and an antennapattern can be arranged in the first and second wiring layers 6 a, 6 band in the third and fourth wiring layers 9 a, 9 b.

Respective functional elements are electrically connected by the signalwiring pattern 14, the power supply pattern 15, and the ground pattern16 by way of via holes 17 and through holes 18 which penetrate the firstdielectric substrate 5 and the second dielectric substrate 8 with theirinner surfaces copper-plated. Specifically, when providing the basesubstrate 2 with the via holes 17 and the through holes 18, holes arebored through the base substrate 2 using a drill or by irradiating alaser beam. And, the via holes 17 and the through holes 18 have theirinner surfaces plated using metal material having conductivity such ascopper. Thus, the signal wiring pattern 14, the power supply pattern 15,and the ground pattern 16 are electrically connected.

The base substrate 2, which are formed by putting the substrate 7 andthe second wiring substrate 10 both made of comparatively inexpensiveorganic material together, can be formed with a lower cost as comparedwith the conventional case using a comparatively expensive Si substrateor glass substrate.

The base substrate 2 is not restricted to above-described configuration,and the number of layers or substrates can be arbitrarily determined.Also, the manner of forming the base substrate 2 is not restricted toabove-described case of putting the first wiring substrate 7 and thesecond wiring substrate 10 together via the preimpregnation substrate11, and copper foils with resin may be layered on both main surfaces ofthe first wiring substrate 7 and the second wiring substrate 10.

The smoothed layer 3 is a buildup surface which smooths the upper layerof the base substrate 2, that is the fourth wiring layer 9 b formed onthe second dielectric substrate 8, with high accuracy. Specifically, informing the buildup surface, an insulating film made of organic materialexcellent in high-frequency characteristics is formed on the whole upperlayer of the base substrate 2 in the first place, and then thus formedinsulating film is polished until the fourth wiring layer 9 b is exposedto outside. In result, the insulating film is formed on concave portionson the second dielectric substrate 8 on which the fourth wiring layer 9b is not formed such that concave portions are removed, that is, theupper layer of the base substrate 2 is smoothed. Thus, the upper layerof the base substrate 2 is smoothed by the smoothed layer 3 with highaccuracy.

Next, in forming the high-frequency element layer 4, an insulating layer19 is formed on the buildup surface in the first place, and then passiveelements such as inductors 20, 21, 22, 23, capacitors, and resistors arearranged in the inner layer or in the outer layer of the insulatinglayer 19 by the thin-film forming technique and the thick-film formingtechnique. In the high-frequency element layer 4, these passive elementssuch as inductors 20, 21, 22, 23, etc. are electrically connected to thepattern wiring layers via wiring patterns 24, embedded conductors 25.The insulating layer 19 of the high-frequency element layer 4 ispreferably made of organic material having low dielectric constant andlow loss tangent (low tan δ), that is, organic material excellent inhigh-frequency characteristics. Also, such organic material preferablyhas refractoriness and chemical resistance. As such organic material,there are benzocyclobutene (BCB), polyimide, polynorbornene (PNB),liquid polymer (LCP), epoxy resin, and acrylic resin. The insulatinglayer 19 is formed by coating the buildup surface with such organicmaterial by using coating methods excellent in coating uniformity andfilm thickness control with high accuracy such as the spin coating,curtain coating, roll coating, dip coating, etc.

Also, on the upper layer of the high-frequency element layer 4, thereare arranged semiconductor chips 26 by the flip chip bonding. Under theprocessing of the flip chip bonding, bumps 27 are formed on electrodesof the semiconductor chips 26, and then the semiconductor chips 26 areconnected to the high-frequency element layer 4 by the face downbonding. That is, the bumps 27 and electrodes 28 of the wiring patterns24 of the high-frequency element layer 4 are put together to be heatedand melted after upsetting and positioning the semiconductor chips 26.By employing the flip chip bonding, space for wiring becomes unnecessaryas compared with the wire bonding, and the dimension along especiallythe height direction can be significantly reduced.

The passive elements and the semiconductor chips 26 formed in and on thehigh-frequency element layer 4 are electrically connected to the fourthwiring layer 9 b of the base substrate 2 via the wiring patterns 24 andthe embedded conductors 25.

According to the high-frequency module 1 employing the presentinvention, since the base substrate 2 is composed of multiple layers,the number of layers of the high-frequency element layer 4 can bereduced. That is, according to the high-frequency module 1 employing thepresent invention, the passive elements and the pattern wiring layerssuch as the wiring patterns 24, the embedded conductors 25 are arrangedin the inner layer or in the outer layer of the high-frequency elementlayer 4, while the functional elements and the pattern wiring layer suchas the signal wiring pattern 14 are arranged in the inner layer or inthe outer layer of the base substrate 2. Thus, burden on thehigh-frequency element layer 4 can be significantly reduced as comparedwith the conventional case in which the whole passive and functionalelements as well as pattern wiring layers are arranged on a Si substrateor on a glass substrate. So, the number of layers of the high-frequencyelement layer 4 can be reduced, and the high-frequency module 1 can bereduced in size further and the manufacturing cost can also be lowered.

According to the high-frequency module 1 employing the presentinvention, since the pattern wiring layers of the base substrate 2 andthose of the high-frequency element layer 4 are separated, electricalinterference raised between those pattern wiring layers can besuppressed, which improves the characteristics of the pattern wiringlayers.

Furthermore, according to the high-frequency module 1 employing thepresent invention, since the upper layer of the base substrate 2 issmoothed by the smoothed layer 3 being a buildup surface, thehigh-frequency element layer 4 can be formed on the buildup surface withhigh accuracy.

In the high-frequency module 1 employing the present invention, the basesubstrate 2 is provided with wiring inhibition regions 30, 31, 32, 33where the first and second wiring layers 6 a, 6 b and the third andfourth wiring layers 9 a, 9 b are not formed from the upper layer to thebottom or to the mid portion thereof along the thickness direction. And,the inductors 20, 21, 22, 23 of the high-frequency element layer 4 areformed directly above the wiring inhibition regions 30, 31, 32, 33.

Specifically, the wiring inhibition region 30 is a region correspondingto part of the high-frequency element layer 4 where the inductor 20 isarranged and part of the base substrate 2 beginning from the upper layerto the second wiring layer 6 b thereof, as shown in FIG. 2.

That is, the fourth wiring layer 9 b is provided with a first wiringinhibition hole 34 directly under the inductor 20, as shown in FIG. 2and FIG. 3A, while the third wiring layer 9 a is provided with a secondwiring inhibition hole 35 also directly under the inductor 20, as shownin FIG. 2 and FIG. 3B. And, the ground pattern 16 formed on the secondwiring layer 6 b and the inductor 20 are so located as to face eachother through the first wiring inhibition hole 34 and the second wiringinhibition hole 35 with a predetermined distance maintainedtherebetween, as shown in FIG. 2 and FIG. 3C.

On the other hand, the inductor 20 is located in the inner layer or inthe outer layer of the insulating layer 19, and has a thin film coilpattern 20 a in the form of a square-shaped spiral, an embeddedconductor pattern 20 b electrically connected to the inner end of thethin film coil pattern 20 a, and a pullout conductor pattern 20 celectrically connected to the embedded conductor pattern 20 b, as shownin FIG. 2 and FIG. 4. The pullout conductor pattern 20 c is pull outfrom the embedded conductor pattern 20 b to the outside of the thin filmcoil pattern 20 a, and the outer end of the thin film coil pattern 20 aas well as the outer end of the pullout conductor pattern 20 c areelectrically connected to the wiring patterns 24 via the embeddedconductors 25.

In forming the inductor 20, specifically, a first insulating layer 19 amade of above-described organic material is formed on the smoothed basesubstrate 2 in the first place, as shown in FIG. 2.

Next, a conductive film made of conductive metal material such as nickel(Ni) or copper (Cu) is formed on the whole first insulating layer 19 a,and then the base of the pullout conductor pattern 20 c is formed byetching the conductive film using a photoresist as a mask which ispatterned to be of a predetermined shape under the photolithographytechnique. Then, the pullout conductor pattern 20 c is completed byperforming electrolytic plating using cupric sulfate solution to form aconductive film of several μm in thickness made of Cu, as shown in FIG.2 and FIG. 5A.

Next, a second insulating layer 19 b made of above-described organicmaterial is formed on the first insulating layer 19 a having the pulloutconductor pattern 20 c formed thereon. Then, a via (hole) is formed suchthat the inner end of the pullout conductor pattern 20 c is exposed tooutside by etching the second insulating layer 19 b using a photoresistas a mask which is patterned to be of a predetermined shape under thephotolithography technique, as shown in FIG. 2 and FIG. 5B. Then, aconductive film made of Cu is formed by performing electrolytic platingusing cupric sulfate solution with the photoresist left on the secondinsulating layer 19 b. Then, the photoresist together with theconductive film formed thereon are removed. In result, the embeddedconductor pattern 20 b embedded into the second insulating layer 19 band the pullout conductor pattern 20 c are electrically connected.

Next, a conductive film made of conductive metal material such as nickel(Ni) or copper (Cu) is formed on the whole second insulating layer 19 b,and then the base of the thin film coil pattern 20 a is formed byetching the conductive film using a photoresist as a mask which ispatterned to be of a predetermined shape under the photolithographytechnique. Then, the thin film coil pattern 20 a which is electricallyconnected to the embedded conductor pattern 20 b is completed byperforming electrolytic plating using cupric sulfate solution to form aconductive film of several μm in thickness made of Cu, as shown in FIG.2 and FIG. 5C.

As shown in FIG. 2, the thickness A of the inductor 20 is preferably 10μm or more as well as one and half time of the winding space B or less.

By employing above-described plating method, the thickness A of theinductor 20 can be increased as compared with the case employing theconventional sputtering method in which the film thickness isapproximately only from 0.5 to 2 μm. Since the thickness A of theinductor 20 becomes more than 10 μm, the series resistance value of theinductor 20 can be reduced, and high Q value of the inductor 20 can beobtained. On the other hand, when the thickness A of the inductor 20 isone and half time of the winding space B, that is space between adjacentwindings of the thin film coil pattern 20 a or less, the inductor 20 canbe formed with high accuracy.

Also, the inductor 20 may be formed to be of the predetermined thicknessA by other thick-film forming techniques different from above-describedplating method.

Furthermore, the inductor 20 is not restricted to the square-shapedspiral in shape shown in FIG. 4, and may be in the form of acircular-shaped spiral, as shown in FIG. 6.

Other inductors 21, 22, 23 are of the same shape as that of the inductor20, and are also formed similarly. So, detailed description will beomitted.

As in the above, in the high-frequency module 1 employing the presentinvention, the base substrate 2 is provided with wiring inhibitionregions 30, 31, 32, 33 where the first and second wiring layers 6 a, 6 band the third and fourth wiring layers 9 a, 9 b are not formed from theupper layer to the bottom or to the mid portion thereof along thethickness direction. And, the inductors 20, 21, 22, 23 of thehigh-frequency element layer 4 are formed directly above the wiringinhibition regions 30, 31, 32, 33. Thus, it becomes possible for thehigh-frequency module 1 to have a space between the inductors 20, 22, 23and the ground patterns 16, which can significantly reduce the couplingcapacitance between the inductors 20, 22, 23 and the ground patterns 16.Furthermore, since the inductor 21 of the high-frequency element layer 4is formed directly above the wiring inhibition region 31 where the firstand second wiring layers 6 a, 6 b and the third and fourth wiring layers9 a, 9 b are not formed from the upper layer to the bottom of the basesubstrate 2, the characteristics of the inductor 21 can further beimproved.

Thus, high Q value of the inductors 20, 21, 22, 23 can be obtained, andimproved characteristics of the inductors 20, 21, 22, 23 can be obtainedin a simplified configuration as compared with the case employing an Sisubstrate in which, inductors are arranged on the Si substrate, and theSi substrate is provided with holes directly under the inductors, orspace is prepared between the inductors and the Si substrate. In result,by employing the high-frequency module 1, the characteristics of theinductors 20, 21, 22, 23 can further be improved, and miniaturizationand decreasing in weight of a communication terminal equipment becomespossible.

INDUSTRIAL APPLICABILITY

As in the above, according to the high-frequency module employing thepresent invention, since the inductors are formed directly above theregions where the pattern wiring layers of the base substrate are notformed, the coupling capacitance between the inductors and the patternwiring layers can be reduced, and high Q value of the inductors can beobtained. In result, by employing the high-frequency module, thecharacteristics of the inductors can further be improved, andminiaturization and decreasing in weight of a communication terminalequipment becomes possible.

What is claimed is:
 1. A high-frequency module, comprising: a substratemade with organic material and having multiple alternating patternwiring layers and dielectric insulating layers made with organicmaterial, a buildup surface layer on an upper surface of the substrate,an insulating layer on the buildup surface; and a high frequency elementlayer formed over the buildup surface, the high frequency element layerincluding an insulating layer on the buildup surface, and an inductorinsulated from the buildup surface by the insulating layer, wherein, thesubstrate has a wiring pattern-free region void of any wiring pattern,the wiring pattern-free region extending from the upper surface to atleast a mid section of the substrate along the thickness direction ofthe substrate, and the inductor of the high-frequency element layer islocated directly above the wiring pattern-free region along thethickness direction of the substrate.
 2. The high-frequency module ofclaim 1, wherein the wiring pattern-free region extends to a bottomsurface of the substrate such that the wiring pattern-free region isvoid of any wiring pattern within the substrate.
 3. The high-frequencymodule of claim 1, wherein the inductor is a thick-film inductor.
 4. Thehigh-frequency module of claim 1, comprising a plurality of inductors inthe high frequency element layer, and a like plurality of correspondingwiring pattern-free regions in the substrate.
 5. The high-frequencymodule of claim 4, wherein all inductors in the high frequency elementlayer have a corresponding wiring pattern-free region in the substrate.